This invention relates to a system for thin-wall casting of concrete structures, particularly thin-wall concrete forms for poured concrete columns and thin-wall panels, usable individually as panel elements or paired as concrete forms for concrete walls.
Typically, concrete columns are cast on the building site using wooden or metal forms that are laboriously erected on site around a network of steel reinforcing bar projecting from a base or footing. The use of a pre-cast concrete form that becomes an integral part of the poured concrete column would save considerable time in the formation of a structure, particularly where numerous columns are required in a building structure.
The use of wooden or metal forms requires considerable labor to assemble the forms and provide the bracing to withstand the hydrostatic pressure of the poured concrete, particularly as the height increases. Additional labor is required to remove and store, or dispose of, the form material after the poured concrete sets. The use of pre-cast concrete forms is clearly advantageous, given the rigid nature of cured concrete. However, the use of pre-cast concrete forms has the disadvantage of the material weight of concrete requiring the wall thickness to be minimized. Without the use of pressure injection or the use of expensive specialty concrete mixtures, the fabrication of relatively lightweight pre-cast column forms is problematic and elusive. Although pre-cast column forms for poured in-place structures have been proposed, the pre-cast forms are typically cast as shell structures in horizontal form molds. Pairs of channel-like shell structures are coupled together with ties to form the vertical column forms. The resulting seams are undesirable, weaken the structure and require finishing for appearance. Additionally, horizontal pre-casting of the form elements results in a lack of perimeter uniformity when erected and interconnected as a column form.
The present invention provides a system of pre-casting column forms and other thin-wall structural elements in a vertical orientation, using a gravity flow pour of standard concrete, or concrete matching the specification of the ultimate column or structural member that is poured on site.
The fabrication system utilizes a slip form technique to achieve a thin wall in the resulting column forms or panels. In the case of the column form, the form can have a square, round or polygonal configuration depending on the desired cross-section of the finished column. The thin-wall panels may be advantageously used in spaced facing pairs with bracing for thicker poured-in-place concrete walls or for pedestals and footings.
These and other advantages in the vertical-cast thin-wall concrete column forms and vertical-cast, thin-wall panels will become apparent from the summary and detailed consideration of the preferred embodiments that follow.